Telescope with variable magnification.



J. HUMBREGHT. TELESCOPE WITH VARIABLE MAGNIFIGATION.

4 APPLIUATIOH FILED MAR. 22, 1912. 1,097,635. Pat nted May 26, 1914.

2 EHEETS-SHEEI' l.

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TELESCOPE WITH VARIABLE MAGNIFIGATION.

APPLICATION FILED MAR. 22, 1912. 1,097,635. Patented May 26, 1914.

2 SHEETS-SHEET 2.

coLulllA PLANOORAPH c0. WASHINGTON, B4 c.

UNITED STATES PATENT OFFICE.

JULES HUMBRECI-IT, OF GROSS-LIGHTER-FELIDE, NEAR BERLIN, GERMANY,ASSIGNOR TO THE FIR-M OF OPTISCI-IE ANSTALT C. P. GOERZAIZTIENGESELLSGI-ZAFT, 0F

FR IEDENAU, NEAR BERLIN, GERMANY.

TELESCOPE WITH VARIABLE MAGNIFICATION,

To all whom it may concern:

Be it known that 1, Jones HUMBREGHT, a citizen of the German Empire, andresident of Gross-Lichterfelde, near Berlin, Germany, have inventedcertain new and useful improvements in and Relating to Tele scopes withVariable Magnificatiomof which the following is a specification.

This invention relates to a telescope with variable magnificationprovided with more than one objective and consists in the arrangement ofthe several objective systems in such a manner that same are rotatableabout an axis perpendicular to the optical axis Of the telescope andthat between the objective lenses reflecting surfaces are providedparallel to the axis of rotation of the objectives; the focal lengths ofthe objectives and their distances from the coop erating reflectorsbeing so calculated that the several objectives have the same imageplane. Thi arrangement of the objectives and of the reflectorscooperating therewith results in an instrument wherein the ocularadjustment remains unchanged, whichever objective system is in use.

Two embodiments of telescopes in accordancewith the invention areillustrated in the accompanying drawings in which- Figure 1diagrammatically illustrates the optical system ofa periscopeconstructed according to the invention with two objective systems, Fig.2 showing the two objective systems of the instrument in a positiondiffering from that in Fig. 1. Figs. 3 and 1 are longitudinal sections,partly in elevation, showing one form of periscope, with the device forchanging the position of the objective systems. Fig. 5 shows the opticalsystem of periscope with three objective systems in one rotatablecarrier and a plurality of partly double sided reflectors.

Refer ing more particularly to Figs. 1 to 4: of the drawings 1represents the objective with the smaller focal length, 2 the positiveelement and 3 the negative element of the objective with the greaterfocal length, 4

Specification of Letters Patent.

Application filed March 22, 1912.

Patented May 26, 191%.

Serial No. 685,403.

a surface reflective on both sides, 5 a collective lens and 6 theunvarying focal plane common to both objective systems when in workingposition; '7 is a reversing system of lenses, 9 an interposed reflector,10 the collective lens of the ocular, and 11 the image plane of theocular.

The passage of two rays belonging to a pencil of parallel rays enteringthe instrument is shown in Fig. 1. From Fig. 2 it will be seen that withthe ocular systems arranged as shown in this figure, the rays passmgthrough the objective 1 of shorter focal length are united in the sameimage plane 6 as the rays which pass through the objec tive 2, 3 ofgreater focal length with the adustment as shown in Fig. 1. Theadjustment of the objective systems as shown in Fig. 2 therefore gives asmaller magnification than that in Fig. 1. With the parts adjusted asshown in Fig. 1 the positive objective element 2 is in front of thereflector surface 4, whereas with the arrangement shown in Fig. 2, it isbehind that surface. By the addition of the negative obective element 3,in the position shown in Fig, 1, the aggregate focal length of theobective 2, 3 is increased beyond the measure already attained byplacing the positive element in front of the reflector surface 1.

As shown in Figs. 3 and l of the drawing the two objective systems, withthe reflector belonging thereto, are mounted in a casing 12 rotatableabout pivots 13. Rotation is imparted to the casing 12, by means of acord is, passing over a pulley 15 mounted on one of the pivots 13, andalso over an other pulley 16 near the ocular end of the instrument.Rotation of the pulley 16 is effected by means of a crank 17. 18 is aboss on the casing, arranged to abut against two fixed abutment surfaces19, 20. According as the crank 17 is rotated in one or the otherdirection, till the boss 18 strikes one or the other of the abutments19, 20, the objecti re 1 of shorter focal length or the objective 2, 3of greater focal length comes into operamon to the three objectivesystems, 42 is a re' versing system, 43 indicates the image plane of theangular ocular, 44 and 45 is a deviating prism inserted into the'ocular.

The instrument allows three different magnifications depending from thespecial obj ective system which is brought into operative position. Theminimum of magnification re-' sults from the operation of objective 34,the middling magnification from objective 35 and the maximum fromobjective 36; in the last case the rays are reflected after havingpassed the front element by each of thereflectors 38, 39, 37 before theyreach the back element of the objective system.

What I claim is r V 1. A telescope with variable magnification,comprising aplurality of objective systems of different focal lengthsrotatable about an axis perpendicular to the optical axis of thetelescope, each system adjustable at will in the path of the rays comingfrom the object and having the same image plane, when in workingposition, and one or more reflectors parallel with the axis of rotationof the objectives.

2. A telescope with variable magnification comprising two objectivesystems of different focal lengths rotatable about an axis perpendicularto the optical axis of the instrument each system adjustable at will inthe path of the rays coming from the object and having the same imageplane when in working position and a reflector so positioned withrelation to the objective systems that its plane is substantiallyparallel to the axis of rotation of the objective sys tems and that theobjective of smaller focal length in working position is located behindthe reflector whereas at least one element of the objective of greaterfocal length is in working position in front of a reflecting surface.

3. A telescope with variable magnification comprising two ob ectivesystems of d1tferent focal lengths rotatable about an axis perpendicularto the optical axis of the instrument each system adjustable at will inthe path of the rays coming from the object and having the same imageplane when in working position and a reflector so posi tioned withrelation to the objective systems that its plane substantially coincideswith the axis of rotation of the objective systems and that theobjective of smaller focal length in working position is located behindthe rethat its plane is substantially parallel to they axis of rotationof the objectives andv that the objective of smaller focal length whenin working position is behind the reflector whereas the positive elementof the objective of greater focal length when in working position is infront of the reflector and the negative element of said objective behindit.

5. A telescope with variable magnification comprising a plurality ofobjectives of different focal lengths reflectors cooperating and inrigid connection therewith the objective and reflector structurerotatable about an axis substantially perpendicular to the optical axisof the instrument and parallel to the reflecting planes.

6. A telescope with variable magnification comprising two objectives ofdifferent focal lengths and a reflector having two reflecting surfaces,one for the one objective and the other for the other objective, saidreflector and said obj ectivesrigidly connected and rohaving differentfocal lengths and forming real images, and means for bringing the saidobjectives alternately into approximately the same operative locuswithout detaching them from the telescope casing.

9. In a telescope a plurality of objectives having different focal.lengths and forming real images, and means for bringing the saidobjectives alternate 7y into approximately the 5&1110 operative locuswithout detaching them from the telescope casing, at least one of theseobjectives being composed of a collective member and a dispersivemember.

10. In a telescope, a plurality of objectives, of different focallengths and reflecting means therefor, and a common movable mounting forsaid objectives and reflecting means, whereby the several objectives maybe brought at will to the same operative locus.

1n testimony whereof I have signed this 15 specification in the presenceof two subscribing witnesses.

J ULES HUMBRE CHT.

WVit-nesses HENRY HAsPER, lVoLDnMAR HAUPT.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

